Patent Document 1 discloses a wireless power-supplying device which includes a primary coil (power-transmitting coil) for wirelessly supplying electric power to a secondary coil (power-receiving coil) of an electric vehicle and can supply electric power without reducing the power supply efficiency even when the stop position of the electric vehicle deviates. An opening is provided in a front lower portion of the wireless power-supplying device. The wireless power-supplying device includes a plate-shaped primary coil holder that has the primary coil provided therein and is driven so as to be movable back and forth in the horizontal direction through the opening. The primary coil holder is moved in the horizontal direction below the secondary coil of the electric vehicle such that the secondary coil and the primary coil face each other and electric power is wirelessly supplied. In the wireless power-supplying device, the upper edge of the opening comes into sliding contact with the upper surface of the primary coil holder. Even when a foreign object is laid on the primary coil holder (above the primary coil), it is possible to remove the foreign object.